Such a gas sensor is known, for example, from DE 10 2005 020 131 B3 (corresponding to U.S. Pat. No. 7,426,849). Such gas sensors operate with catalytic oxidation of combustible gases, which leads to a rise in temperature at the sensor element, which in turn entails a change in the resistance of the sensor element, which can be measured from the outside via the terminals. Such gas sensors are used, for example, to detect explosive gas mixtures. The sensor element is heated here electrically to a relatively high operating temperature (up to approximately 500° C.). When a combustible gas is present at the surface of the sensor element, this gas is oxidized and a change in the surface temperature of the sensor element is brought about by the heat generated. The gas sensor known from DE 10 2005 020 131 B3 has a housing with a gas inlet opening. The gas inlet opening is closed with a gas-permeable closure, which is said to act as a flame arrester and to prevent hereby flames from being able to break through to the outside in the presence of combustible gases. The closure consists of, e.g., wire mesh or sintered metal bodies. A second sensor element, which does not come into contact with the ambient atmosphere, may be provided. A comparison of the changes in the resistances of the first sensor element and the second sensor element makes it therefore possible to infer which temperature change can be attributed to the oxidation of combustible gas, e.g., by comparing the voltages over the two sensor elements via a Wheatstone bridge. The sensor elements are connected to lines in the form of metal pins, which lead out of the housing of the gas sensor. The lines are passed through openings in the housing of the gas sensor, which are closed with glass seals. The combustible gas to be detected enters this gas sensor through the gas-permeable closure in the inlet opening by diffusion and thus reaches the sensor element in the interior of the container. The gas transport to the reaction element takes place by diffusion and by incidentally occurring changes in the ambient conditions, e.g., due to wind flows. However, the latter may sometimes also have opposite effects, namely, they may hinder the diffusion of the gas molecules to the sensor element.
The consequence of the above-described mode of operation of the gas sensor is a relatively long response time of the gas sensor during the detection of the target gas or target gases. The response times depend, moreover, on the gas species. It is also disadvantageous in respect to the response time that the combustion products of the combustible gas, which arise from the function, collect in the interior of the housing and may hinder as a result the diffusion of the combustible gases to be detected towards the sensor element.